Grounding bands are typically used in electrical connector assemblies, such as plug and receptacle assemblies, to provide both grounding and EMI shielding. The grounding band fills in the gap between the electrical connectors of the assembly, such as a plug and receptacle. The grounding band maintains a conductive path between the electrical connectors.
Conventional grounding bands are formed typically by welding the ends of the strap that forms the band. More specifically, the ends of the grounding band are typically spot welded. Spot welding poses a number of problems. Welding is costly and material variations affect the precision of the weld. Spot welding requires physical contact of electrodes on both sides of the overlapped ends of the band. Due to the very small size of the spot weld region, however, small diameter electrodes with specially shaped tips are required. Also, change in the physical shape of the electrodes and the amount of foreign material on the electrode surface often have a negative impact on the weld's internal structure. Welded bands are prone to failure because of process variables and reliance on operator skill to properly align the ground strap ends during the welding operation. As the electrodes are used, each welding cycle causes additional foreign material to collect on the electrode face. This in turn changes the electrical resistance between the electrode and the objects being welded. When the resistance increases between the electrode and the workpiece, less energy is available for the intended welding of the product. Because of this change, the weld strength must be tested. That testing can only be done by destroying the band.
Moreover, although periodic cleaning of the electrodes can be done by use of an abrasive cloth, over time, that changes the shape of the electrodes requiring replacement of the electrodes. Replacement of the electrodes takes time away from production. Following the replacement, the weld must be tested resulting in more grounding band material being wasted.
Also, the conventional method of overlapping leaves at the ends of the grounding band strap significantly increases the thickness of the band at that point. Because of the limited clearance between the two mated connector elements (i.e. the plug and receptacle) and additional thickness added to the band could prevent proper mating of the connector elements. This overlapping causes a misalignment of the ends of the grounding band. This misalignment condition can cause loss of continuity between the ends of the grounding band when on a plug connector and the inner wall of a receptacle connector thus reducing the electrical path between the two connectors and the effectiveness of the EMI shielding.